Fluid control valves may contain a valve and valve seat that controls the flow of fluid between two or more connection ports located in the valve housing. The flow of fluid between the connection ports is determined by the position of the valve relative to the valve seat. By way of example, in a two-way valve, when the valve is lifted away from the seat, a first connection port is in fluid communication with a second connection port. When the valve is in contact with the valve seat, the fluid communication between the first and second connection ports is blocked. The position of the valve is typically controlled by one or more actuators such as electrical solenoids.
Fluid control valves must provide a force to hold the valve in the desired operating position. Typically the fluid being controlled will be under pressure and the pressure of the fluid will produce a net pressure force on the valve that must be overcome by the fluid control valve to hold the valve in the desired operating position. This increases the force that must be provided by the fluid control valve. If the fluid pressure forces vary depending on the valve position or the pressure of the controlled fluid, additional complexities are introduced into designing a valve that operates efficiently and reliably under a range of conditions.
Dynamically unbalanced valves may require the actuators to overcome the pressure of the fluid to move or hold the valve. The additional work required to overcome the fluid pressure consumes more power and reduces the energy efficiency of the system. Therefore it would be desirable to provide a fluid control valve that is dynamically balanced.
A dynamically balanced fluid control valve controls a fluid between two connection ports. A tube couples two diaphragms at opposing ends of the tube. A valve is coupled to the tube between the opposing ends to control a valve port. Actuators move the transfer tube to move the valve. The diaphragms dynamically balance the force exerted by the fluid on the valve.